1. Field of the Invention
This invention relates to a method and apparatus for casting steel reinforced concrete structures and especially to pre-casting steel reinforced rectangular concrete structures for use as room modules in housing. Most particularly, the invention relates to a new and improved method and apparatus for maximising the production and reducing the cost of steel reinforced pre-cast room modules by an assembly line.
2. The Prior Art
Concrete fabrication falls into two major categories: cast in place concrete and pre-cast concrete. Cast in place concrete has the advantage of permitting a great deal of flexibility as to the form or shape of the structure being made, whereby to yield building configurations that are not readily achievable with any other known method of fabrication. However, cast in place concrete methods are basically tailor-made methods and are therefore quite costly of time, labor and materials. They often require the establishment of an elaborate facility at the construction site.
The other process commonly employed in fabricating buildings from concrete is the use of pre-cast concrete. This manifests itself in different forms such as pre-cast concrete beams which are incorporated in buildings otherwise built at the site, or precast slabs to form floors on skeletal steel buildings, the construction of pre-cast slabs which are then joined together at site to form rooms and the formation of rectangular box like structures that can serve as an enclosure for one or more rooms. The latter two of these techniques of pre-casting have lent themselves to some degree of mechanization, whereby to increase the productivity of the labor and reduce costs. As a result it has been heretofore recognized that the pre-casting of concrete, including the pre-casting of concrete rectangular modules does provide an opportunity for increased production at lower costs.
There are numerous attempts in the prior art to facilitate the production of pre-cast reinforced concrete structures. U.S. Pat. No. 3,689,019 granted to Joseph W. Ferenc on Sept. 5, 1972 for Apparatus for Shuttering Poured Concrete Structures discloses a method and apparatus for forming inverted U-shape reinforced concrete structures. However, Ferenc does not confront the problem of maximizing such production especially when there is an overhead concrete ceiling to be supported. Moreover, while the internal form for the U-shaped member is movable, there is no suggestion of progressing it or the external form from location to location to maximize production. In fact, Ferenc visualizes the use of his apparatus to casting in place. Similarly, in U.S. Pat. No. 3,696,177 granted to Harry L. Holland on Oct. 3, 1972 for Method For Forming Concrete Box Culverts And The Like, a method and apparatus is disclosed for forming a hollow tunnel like structure out of concrete. However, the apparatus includes a unitary internal form that cannot be moved in whole or in part until the entire roof of the culvert is able to support itself, whereby to reduce the productivity of the form. Secondly, despite the fact that the internal form in the Holland patent is provided with casters, there is no suggestion of utilizing such a form with a series of separate casting beds and progressing the form from bed to bed for the purpose of creating an assembly line for the formation of reinforced concrete structures. In fact, the Holland patent does not even consider the longitudinal movability of the external form, it being apparent from the disclosure that they are moved only perpendicularly of their forming plane. Thus the Holland structure is not susceptible for use in an assembly line type operation. In U.S. Pat. No. 3,834,110 granted to Michele Verselute on Sept. 10, 1974 for Method For The Manufacture of Prefabricated Housing Units, a method of making such rectangular concrete structures is described. However, this method requires the pre-casting of separate slabs forming the various surfaces and then the joining of the slabs by additional poured concrete.
Other prior art patents of lesser interest but known to applicant are Quentin U.S. Pat. No. 3,482,005 granted on Dec. 3, 1969 for Method Of Constructing Concrete Building and U.S. Pat. No. 3,963,395 granted to John L. Bordo on June 15, 1976 for Mass Production Line For Fabricating Structural Building Members.